A comprehensive approach to the bilingual influence on cognition in younger adults and adolescents: the role of the wider social context

Bilingualism has been suggested to benefit cognitive performance; however, this claim has recently been highly debated (Chapter 1). We hypothesized that this effect might be influenced by the wider social context of the bilingual experience, thus emerging only in specific populations. In this Thesis, I examined whether the acculturation strategy adopted by bilinguals in the host society might modulate the effect of bilingualism on cognitive control. The bilingual sample was divided into a Bicultural and a Monocultural group, and compared to a matched Monolingual group. I also examined whether the overall bilingual profile – including linguistic, affective, socio-cultural and educational characteristics – might modulate the effect of bilingualism on cognitive control. Such a comprehensive approach to the bilingual cognitive advantage has not been adopted thus far. Using cluster analyses, two bilingual groups were formed; a Balanced profile and an Unbalanced (dominant) profile group. Lastly, I examined whether age might play a role in observing the effects of acculturation and bilingual profile, by examining both younger adults (Chapter 2) and adolescents (Chapter 3); the latter being a highly under-studied group. There was no systematic evidence of a bilingual advantage in cognitive control; regardless of age group, acculturation, or overall bilingual profile. However, there was evidence of negative effects of acculturation on cognitive performance, which suggests that the effects of acculturation and bilingualism may have been confounded in previous studies. The only (robust) evidence of a positive bilingualism effect was restricted to selective attention (facilitation), and to Balanced profile adolescent bilinguals. This is consistent with language-specific models of control, and with the hypothesis that the effects of bilingualism on cognition might be more prevalent in younger ages. These findings also emphasize the importance of taking a comprehensive approach to bilingualism. Implications for the bilingual cognitive advantage, and suggestions for future research, are discussed in Chapter 4.